The table
below summarizes information about the Shagawa Lake basin. The
lake has been "sliced" into layers, or slabs, of water
that are 2 meters (6.5 feet) thick. The table reports the volume
of each layer and the surface area at the middle of each layer. Adding
up the layers yields a total volume of 18.9 x 106 m3 (cubic
meters). The surface area of the lake was determined by GIS from
the Landuse maps(lit cite) and equals 344 hectares (3.44 x 106 m2).

To estimate
the area at the top of any layer, use the following formula: Regression
of : Area (hectares) @ top of layer vs depth of layer top (meters)
A(z) = (-20.86)*z + 291.6.